#include <iostream>
using namespace std;

// 无参无返
void test01()
{
  cout << "这是第一个案例" << endl;
}
// 有参无返
void test02(int a)
{
  cout << "这是第二个案例 a = " << a << endl;
}
// 无参有返
int test03()
{
  cout << "这是第三个案例 " << endl;
  return 100;
}
// 有参有返
int test04(int a)
{
  cout << "这是第四个案例 a = " << a << endl;
  return a;
}

int main(int argc, char const *argv[])
{
  test01();
  test02(10);

  int num1 = test03();
  cout << "num1 = " << num1 << endl;

  int num2 = test04(200);
  cout << "num2 = " << num2 << endl;

  return 0;
}